How A Bilateral Varicocele Affects Male Fertility?

A varicocele is an enlarged vein inside the scrotum, and a bilateral varicocele means the condition is present on both sides. It is the most common correctable cause of male infertility, and having it on both sides can affect sperm production more than a one-sided varicocele because a larger share of the testicles is exposed to the same problem.

What Is a Bilateral Varicocele and How Common Is It?

A varicocele is a swelling of the pampiniform plexus — the network of veins that drains blood from each testicle. When those veins lose their one-way valves, blood pools instead of flowing upward. The result is a tangle of enlarged veins above and around the testicle.

Varicoceles are common. They affect roughly 15 in 100 men in the general population. The large majority form on the left side, and the reason is anatomical, not random. The left testicular vein drains into the left renal vein at a sharp angle, while the right drains more directly into the inferior vena cava. That sharper angle, and the higher pressure in the left renal vein, make the left side far more vulnerable.

A bilateral varicocele is much less common than a left-sided one. Estimates vary widely across studies, partly because the two sides are not always evaluated with the same method. A varicocele on the right side alone is uncommon enough that clinicians treat it as a reason to look for a cause behind the testicle, such as a mass pressing on the vein.

Many varicoceles cause no symptoms and are found only during an infertility workup. Others cause a dull ache or heaviness in the scrotum that worsens after standing or physical activity and eases when lying down.

How Does a Bilateral Varicocele Affect Male Fertility?

A varicocele raises the temperature inside the scrotum, and that heat is the central problem. Sperm production depends on a testicular temperature about 2 to 4 degrees Fahrenheit cooler than core body temperature. When pooled blood sits in the veins around the testicle, it acts like a warm blanket.

That sustained heat stresses the sperm-producing tissue in several ways:

• It can reduce the number of sperm produced.
• It can lower the percentage of sperm that move normally.
• It can increase the percentage of sperm with abnormal shape.
• It raises oxidative stress, meaning reactive molecules build up faster than the body can neutralize them.
• In some men it damages sperm DNA, which is separate from how the sperm look under a microscope.

Bilateral disease matters because both testicles are affected. A left-sided varicocele leaves the right testicle in a normal environment. A bilateral varicocele exposes both. In general, the more testicular tissue affected, the more room there is for semen quality to decline — though this is a tendency, not a rule.

What matters most is that the relationship between varicocele and fertility is not straightforward. Many men with a varicocele, including a bilateral one, father children without difficulty. Others have a clear abnormality on semen analysis. The varicocele is a contributing factor, not a verdict.

Does a Bilateral Varicocele Cause Worse Sperm Problems Than a One-Sided One?

The evidence points that direction, but it is not settled. Some studies have found that men with bilateral varicoceles tend to have lower sperm counts and poorer sperm motility than men with a left-sided varicocele only. Other studies have found no meaningful difference between the two groups.

Part of the difficulty is measurement. Not all studies grade both sides the same way, and grading itself is somewhat subjective. A varicocele that one examiner calls small, another may call moderate. That inconsistency makes it hard to compare results across studies.

What is reasonably consistent is that varicoceles in general are found more often in men being evaluated for infertility than in men with proven fertility. That association is well established. Whether the bilateral form is reliably worse than the unilateral form is a question the research has not answered cleanly.

How Is a Bilateral Varicocele Diagnosed?

Diagnosis starts with a physical exam. The man stands, and the clinician examines the scrotum while he bears down or coughs. That maneuver increases pressure in the veins and makes a varicocele easier to feel. A varicocele is often described as feeling like a “bag of worms” above the testicle.

Varicoceles are graded on a clinical scale:

• Subclinical — not detectable by touch or by sight, found only on imaging.
• Grade 1 — felt only when the man bears down.
• Grade 2 — felt without bearing down but not visible.
• Grade 3 — visible through the skin.

Scrotal ultrasound is the usual next step. It confirms the diagnosis, measures the vein diameter, and evaluates both sides. Because bilateral disease requires examining the right side carefully, ultrasound is especially useful here.

Semen analysis is the other essential piece. It measures sperm concentration, total count, motility, and morphology. Because sperm production takes roughly 70 to 90 days to complete a cycle, a single abnormal result is usually repeated after a few months before any conclusions are drawn.

Hormone testing may also be ordered. A varicocele can affect testosterone production in some men, though this varies and is not universal.

Does Treating a Bilateral Varicocele Improve Fertility?

Treatment can improve semen quality in some men, but it does not help everyone, and it does not guarantee a pregnancy. That distinction matters.

The main surgical option is varicocelectomy, which ties off or blocks the enlarged veins. It can be done through a small groin incision, with laparoscopy, or through a percutaneous approach that blocks the veins from inside using a catheter. The goal is the same: redirect blood flow away from the swollen veins so the testicle can cool down.

Research generally shows that a meaningful share of men have improved sperm concentration and motility after surgery. The improvements are real but modest on average, and a substantial minority see no change. Pregnancy rates after varicocele repair are harder to pin down — studies vary in how they are designed, and results have not been uniform.

Not every varicocele needs treatment. A small varicocele in a man with normal semen and no symptoms is often simply monitored. Treatment is more commonly considered when:

• Semen analysis shows abnormal results.
• The varicocele is large or clearly palpable.
• The man has scrotal pain or discomfort.
• Testosterone levels are low and the varicocele appears to be a factor.
• Other causes of infertility have been ruled out.

For men with bilateral disease, some clinicians treat both sides during the same procedure. Whether repairing both sides produces better outcomes than repairing only the larger one is not firmly established. It is a judgment call that depends on the individual case.

Watchful waiting is a legitimate option too. Some men with a varicocele and normal semen parameters never need intervention.

What Else Can Affect Male Fertility Alongside a Varicocele?

A varicocele is rarely the only variable. Many factors shape male fertility, and a bilateral varicocele does not cancel them out.

Age matters. Sperm quality tends to decline gradually with age, though the effect is slower and less predictable than in women. Lifestyle factors also play a role. Smoking, heavy alcohol use, obesity, and prolonged heat exposure — such as frequent hot tubs or tight clothing — can all work against sperm production. So can certain medications, hormone use, and underlying medical conditions.

This is why a full evaluation matters. If a man has a bilateral varicocele and also smokes, treating only the veins may not be enough. And if the varicocele is small and the real problem lies elsewhere, surgery may not help at all.

It is also worth separating what is proven from what is marketed. A long list of supplements claim to boost fertility. For most of them, no large human trials have confirmed a benefit. Some, like antioxidants, have shown mixed results in studies of men with varicoceles. The evidence is not strong enough to present them as a reliable fix.

The bottom line is that a bilateral varicocele is a real, diagnosable condition that can affect sperm production on both sides. It is also one factor among many — and one that a urologist can evaluate and, in some cases, treat.